1. Field of the Invention
The present invention relates to a memory device and an apparatus employing the memory device.
2. Related Background Art
Electronic still cameras employing magnetic floppy disks as the recording medium are already commercialized, but, due to the decreasing cost and increasing level of integration of semiconductor memories, recently there have been proposed electronic still camera systems employing solid-state memories such as semiconductor memories.
When use is made of a solid-state memory apparatus detachable from the camera body and composed of large-capacity integrated circuit (IC) memories as a recording medium, it is necessary to reduce the number of connecting lines which connect the solid-state memory with the camera body and yet still enable rapid access to the memory.
More specifically, the camera body and solid-state memory apparatus are connected by a serial data line and several control lines for the purpose of achieving simpler connection, higher reliability and lower cost, since the usual parallel structure of data lines and address lines, employed in the attached image memory, increases the number of connecting lines, thus deteriorating the reliability and increasing the cost.
A serial data line is ordinarily sufficient when the operating modes of the device do not require random access to the solid-state memory apparatus. However, high-speed random access capability in each image memory unit (block)is required, for example, in a high-speed continuous photographing operation or in random reproduction of the photographed images.